The expanded scope and breath of the Human Retroviruses and Other Emerging Pathogens Activity will involve epidemiological and laboratory-based studies of new, emerging and re-emerging pathogens. In addition, investigatons will be aimed at detecting cryptic microbial genomic sequences in tissues from patients with diseases of suspected infectious. Specifically, attempts will be made to find the etiologic agents for diseases of presumed infectious origin, such as Kawasaki disease, Bechet's syndrome, Viliuisk encephalomyelitis, and chronic fatigue syndrome.